Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A231A6

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N240SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A231A6
Octal
50430646
Decimal
10,629,542
Country
US
Tail
N240SY
Type
E75L
No current signal · last broadcast 6h ago
Flights observed
671
Distinct callsigns
20
Country
US
Last broadcast
6h ago

Last known position

Most recent position reported by Mode-S A231A6.

Country allocation

The ICAO 24-bit address A231A6 falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 20 distinct

Callsign Airline Flights Last seen
SKW4119 - 13 2026-07-03
SKW3841 SkyWest Airlines 13 2026-06-08
SKW3991 - 11 2026-07-01
SKW3894 - 11 2026-07-02
SKW3832 - 10 2026-07-09
SKW4127 - 9 2026-07-12
SKW4099 - 9 2026-07-04
SKW4077 - 9 2026-07-04
SKW3806 - 9 2026-07-11
SKW3802 - 9 2026-06-29
SKW3953 - 8 2026-06-24
SKW3902 - 8 2026-06-22
SKW3828 SkyWest Airlines 8 2026-06-09
SKW3755 - 8 2026-07-02
SKW3750 - 8 2026-07-01
SKW4148 - 7 2026-07-05
SKW3883 - 7 2026-07-03
SKW3743 - 7 2026-07-04
SKW4472 - 6 2026-07-13
SKW4092 - 6 2026-07-06

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 SKW183T - Jul 13, 20:00 UTCJul 13, 21:05 UTC1h 5m
2026-07-13 SKW183T BOI → SEA Jul 13, 20:04 UTCJul 13, 21:00 UTC56m
2026-07-13 SKW3678 - Jul 13, 17:40 UTCJul 13, 18:50 UTC1h 10m
2026-07-13 SKW4471 - Jul 13, 16:15 UTCJul 13, 16:40 UTC25m
2026-07-13 SKW4472 SEA → PDX Jul 13, 06:11 UTCJul 13, 06:35 UTC24m
2026-07-13 SKW4472 SEA → PDX Jul 13, 06:10 UTCJul 13, 06:45 UTC35m
2026-07-13 SKW3923 - Jul 13, 04:00 UTCJul 13, 04:35 UTC35m
2026-07-13 SKW3923 PDX → SEA Jul 13, 03:50 UTCJul 13, 04:30 UTC40m
2026-07-13 SKW3923 SEA → PDX Jul 13, 02:25 UTCJul 13, 03:01 UTC35m
2026-07-12 SKW4174 - Jul 12, 23:15 UTCJul 13, 00:30 UTC1h 15m
2026-07-12 SKW4174 BZN → SEA Jul 12, 23:02 UTCJul 13, 00:17 UTC1h 15m
2026-07-12 SKW4104 SEA → BZN Jul 12, 19:38 UTCJul 12, 20:45 UTC1h 7m
2026-07-12 SKW4104 - Jul 12, 19:35 UTCJul 12, 20:25 UTC50m
2026-07-12 SKW3695 - Jul 12, 15:35 UTCJul 12, 17:45 UTC2h 10m
2026-07-12 SKW3932 - Jul 12, 02:55 UTCJul 12, 05:25 UTC2h 30m
2026-07-12 SKW3932 SEA → SNA Jul 12, 02:50 UTCJul 12, 05:25 UTC2h 35m
2026-07-12 SKW4127 - Jul 12, 00:15 UTCJul 12, 01:20 UTC1h 5m
2026-07-11 SKW4127 SEA → BOI Jul 11, 22:10 UTCJul 11, 23:10 UTC1h 0m
2026-07-11 SKW3878 MFR → SEA Jul 11, 19:55 UTCJul 11, 20:45 UTC50m
2026-07-11 SKW3806 - Jul 11, 16:50 UTCJul 11, 18:20 UTC1h 30m
2026-07-11 SKW3806 SLC → MFR Jul 11, 17:01 UTCJul 11, 18:15 UTC1h 14m
2026-07-11 SKW4006 - Jul 11, 13:15 UTCJul 11, 15:25 UTC2h 10m
2026-07-10 SKW3825 SLC → TUL Jul 10, 23:20 UTCJul 11, 01:20 UTC2h 0m
2026-07-10 SKW3765 - Jul 10, 21:35 UTCJul 10, 22:15 UTC40m
2026-07-10 SKW3765 - Jul 10, 19:40 UTCJul 10, 20:05 UTC25m
2026-07-10 SKW4026 SJC → SLC Jul 10, 17:00 UTCJul 10, 18:25 UTC1h 25m
2026-07-10 SKW4451 - Jul 10, 15:25 UTCJul 10, 16:15 UTC50m
2026-07-10 SKW4115 - Jul 10, 12:50 UTCJul 10, 14:25 UTC1h 35m
2026-07-10 SKW4098 - Jul 10, 04:05 UTCJul 10, 05:40 UTC1h 35m
2026-07-10 SKW4091 ABQ → LAX Jul 10, 01:00 UTCJul 10, 02:40 UTC1h 40m
2026-07-09 SKW4091 - Jul 9, 22:15 UTCJul 10, 00:00 UTC1h 45m
2026-07-09 SKW3744 - Jul 9, 20:10 UTCJul 9, 21:15 UTC1h 5m
2026-07-09 SKW3680 SEA → TUS Jul 9, 16:00 UTCJul 9, 18:45 UTC2h 45m
2026-07-09 SKW3680 SEA → TUS Jul 9, 15:37 UTCJul 9, 18:45 UTC3h 8m
2026-07-09 SKW4128 EUG → SEA Jul 9, 13:25 UTCJul 9, 14:10 UTC45m
2026-07-09 SKW3855 SEA → EUG Jul 9, 06:10 UTCJul 9, 06:55 UTC45m
2026-07-09 SKW3832 GEG → SEA Jul 9, 03:15 UTCJul 9, 03:52 UTC37m
2026-07-09 SKW3832 GEG → SEA Jul 9, 03:10 UTCJul 9, 04:05 UTC55m
2026-07-09 SKW3832 SEA → GEG Jul 9, 01:35 UTCJul 9, 02:15 UTC40m
2026-07-08 SKW3789 SJC → SEA Jul 8, 22:25 UTCJul 9, 00:20 UTC1h 55m
2026-07-08 SKW168F SEA → SJC Jul 8, 19:30 UTCJul 8, 21:25 UTC1h 55m
2026-07-08 SKW156H GEG → SEA Jul 8, 17:15 UTCJul 8, 18:05 UTC50m
2026-07-08 SKW3830 SEA → GEG Jul 8, 14:40 UTCJul 8, 15:20 UTC40m
2026-07-08 SKW4008 PDX → SEA Jul 8, 12:50 UTCJul 8, 13:20 UTC30m
2026-07-08 SKW4472 SEA → PDX Jul 8, 06:50 UTCJul 8, 07:25 UTC35m
2026-07-08 SKW4472 SEA → PDX Jul 8, 06:40 UTCJul 8, 07:21 UTC41m
2026-07-08 SKW3887 YVR → SEA Jul 8, 03:00 UTCJul 8, 03:40 UTC40m
2026-07-08 SKW132K SEA → YVR Jul 8, 01:15 UTCJul 8, 01:40 UTC25m
2026-07-07 SKW4125 CMH → DTW Jul 7, 20:10 UTCJul 7, 21:45 UTC1h 35m
2026-07-07 SKW4125 CMH → DTW Jul 7, 17:40 UTCJul 7, 19:05 UTC1h 25m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Prefer a tail-number view? See the N240SY page for operator, model, and routing details .

Mode-S A231A6 frequently asked

What is Mode-S code A231A6?
A231A6 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N240SY.
Where is Mode-S A231A6 registered?
Mode-S code A231A6 is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A231A6 broadcasting right now?
No active broadcast right now. Last signal was 6h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A231A6, octal 50430646, decimal 10,629,542.
What flights does A231A6 operate?
Mode-S A231A6 has broadcast 20 distinct callsigns, including SKW4119, SKW3841, SKW3991, SKW3894, SKW3832.